JP2007175093A - Absorbent article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an absorbent article having an excellent liquid drawability and spot absorbing property which prevents liquid from remaining on its surface. <P>SOLUTION: The absorbent article 1 comprises a surface sheet 2, a rear sheet 3 and an absorptive core 4 sandwiched between the two sheets. The surface sheet 2 is made of a nonwoven fabric 20 having a plurality of heat welding parts 23 formed by embossing. Fibers forming the nonwoven fabric between the heat welding parts 23 forms a plurality of projections 24 at least in the skin facing surface side of the nonwoven fabric 20. The absorptive core 4 is made of an absorptive sheet 40 containing hydrophilic fibers, heat welding adhesive fibers or a paper strength reinforcing agent, and a super absorbent polymer. The nonwoven fabric 20 forming the surface sheet and the absorptive sheet 40 forming the absorptive core contact with each other directly. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an absorbent article such as a sanitary napkin, a panty liner (cage sheet), and an incontinence pad.

Conventionally, in an absorbent article such as a sanitary napkin, a fiber assembly layer called a second sheet, a sublayer, or a cushion material is provided between the top sheet and the absorbent core in order to improve liquid return and cushioning properties. (See Patent Documents 1 and 2)
However, in the conventional technique, since a space is formed between the top sheet and the fiber assembly layer, the liquid transferability is poor and a sufficient absorption rate cannot be obtained.

In addition, the applicant previously described the first fiber layer containing three-dimensionally crimped fibers as a bulky and soft sheet material that has high liquid drawability and can absorb liquid quickly, and the same or different types of fibers. And the second fiber layer containing the three-dimensional crimped fiber of the three-dimensional crimped fiber, the degree of crimp of the three-dimensional crimped fiber contained in the second fiber layer is the three-dimensional crimped fiber contained in the first fiber layer. A sheet material in which the apparent density of the second fiber layer is higher than the apparent density of the first fiber layer is proposed (see Patent Document 3). This sheet material is also suitable as a top sheet for absorbent articles such as sanitary napkins and disposable diapers.
However, the demands for absorbent articles are increasing, and there is a demand for a device that further increases the absorption rate and that is further superior in preventing the liquid from returning.

JP-A-8-164160 Japanese Unexamined Patent Publication No. 2-4368 JP 2002-187228 A

  Accordingly, an object of the present invention is to provide an absorbent article that is excellent in liquid drawability, hardly causes liquid residue on the surface, and has excellent spot absorbability.

  The present invention is an absorbent article comprising a top sheet, a back sheet, and an absorbent core interposed between the two sheets, the top sheet having a number of heat-sealed portions formed by embossing. The non-woven fabric, and the fibers constituting the non-woven fabric between the heat-sealed portions protrude to at least the skin-facing surface side of the non-woven fabric to form a large number of raised portions, and the absorbent core includes hydrophilic fibers and , A heat-meltable adhesive fiber or a paper strength reinforcing agent, and an absorbent sheet containing a superabsorbent polymer, and the nonwoven fabric constituting the top sheet and the absorbent sheet constituting the absorbent core are in direct contact with each other The above object is achieved by providing an absorbent article.

  The absorbent article of the present invention is excellent in liquid drawability while maintaining cushioning properties, hardly causes liquid residue on the surface, and is excellent in spot absorbability.

The present invention will be described below based on preferred embodiments with reference to the drawings.
As shown in FIGS. 1 and 2, a sanitary napkin 1 (hereinafter also referred to as a napkin 1) as an embodiment of the absorbent article of the present invention includes a liquid-permeable topsheet 2, a liquid-impermeable (hard). (Including permeability) of the back sheet 3 and the absorbent core 4 disposed between the two sheets.
Each of the top sheet 2 and the back sheet 3 has a shape that substantially matches the plan view shape of the napkin 1. On both side portions of the napkin 1 in the longitudinal direction, side sheets 5 made of a water-repellent nonwoven fabric are disposed along the longitudinal direction of the napkin 1.
The side sheet 5, the top sheet 2, and the back sheet 3 are integrally formed by heat embossing in a state of being laminated in this order. In the central region in the width direction of the napkin 1 where the side sheet 5 does not exist, the top sheet 2 and the back sheet 3 are integrated by hot embossing.

  As shown in FIG. 2, the surface sheet 2 in the napkin 1 is composed of a nonwoven fabric 20 having a large number of heat-sealed portions 23 formed by embossing, and the fibers constituting the nonwoven fabric are formed between the heat-fused portions 23. A plurality of raised portions 24 are formed so as to protrude to at least the skin-facing surface side (the surface side facing the wearer's skin when the absorbent article is used) of the nonwoven fabric.

The nonwoven fabric 20 which comprises the surface sheet 2 is demonstrated in detail.
As shown in FIG. 2, the nonwoven fabric 20 has a two-layer structure including an upper fiber layer 21 and a lower fiber layer 22 adjacent thereto. The upper fiber layer 21 is composed of a fiber assembly. The lower fiber layer 22 is composed of an aggregate of fibers of a different type and / or blend from the fibers constituting the upper fiber layer 21. The upper fiber layer 21 and the lower fiber layer 22 are partially joined by a large number of heat-sealed portions 23 formed by embossing.

  The heat-sealing part 23 is small and discretely formed discontinuously, and forms a staggered arrangement pattern as a whole. The heat-sealing part 23 is consolidated and has a smaller thickness and a higher density than other parts of the nonwoven fabric 20. The upper fiber layer 21 and the lower fiber layer 22 are integrated in the thickness direction by the heat fusion part 23. Although the heat fusion part 23 in this embodiment is circular, the shape of the heat fusion part 23 may be an ellipse, a triangle, a rectangle, or a combination thereof. Further, the heat fusion part may be formed in a continuous shape, for example, a linear shape such as a straight line or a curved line.

In the nonwoven fabric 20, the fiber which comprises this protrudes in the thickness direction of the nonwoven fabric 20 between the heat-fusion parts 23 (skin contact surface side). As a result, a large number of raised portions 24 are formed on the skin contact surface side of the nonwoven fabric. On the surface of the nonwoven fabric 20 on the absorbent core 4 side, the portion having the heat-sealed portion 23 is slightly recessed as compared to the surrounding area.
The raised portion 24 is composed of the upper fiber layer 21. In the nonwoven fabric 20 used in the present embodiment, a large number of substantially square regions having the heat fusion portions 23 at four corners are formed, and in each region, the upper fiber layer 21 is as shown in FIG. A raised portion 24 is formed so as to protrude. The raised portion 24 in the present embodiment has a dome shape, and the inside thereof is filled with fibers constituting the fiber layer. The heat fusion part 23 is a concave part relative to the raised part 24.
In addition, the height T from the heat fusion part 23 of the protruding part 24 can be about 0.3-5 mm, for example. The height of the raised portion 24 is measured by observing the longitudinal section of the nonwoven fabric 20 with a microscope.

  The lower fiber layer 22 in the nonwoven fabric 20 used in the present embodiment includes latent crimpable fibers in which crimps are expressed. The latent crimpable fiber in which crimps are expressed is in a coiled crimped state. The latent crimpable fiber preferably has a fineness of about 1 to 7 dtex. The latent crimpable fiber includes, for example, an eccentric core-sheath type composite fiber or a side-by-side type composite fiber containing two types of thermoplastic polymer materials having different shrinkage rates as components. Examples thereof include those described in JP-A-9-296325 and Japanese Patent No. 2759331. As an example of two types of thermoplastic polymer materials having different shrinkage rates, for example, a combination of an ethylene-propylene random copolymer (EP) and polypropylene (PP) is preferably exemplified. The latent crimpable fiber in which crimps are expressed is preferably contained in the lower fiber layer 22 in an amount of 50% by weight or more, particularly 70 to 90% by weight from the viewpoint of the formation of the raised portion 24. The lower fiber layer 22 may be composed of 100% latent crimpable fibers in which crimps are developed. When the lower fiber layer 22 includes fibers other than the latent crimpable fibers in which crimps are developed, the fibers include heat fusion that does not substantially shrink at the crimp start temperature of the latent crimpable fibers. For example, an attached fiber may be used. Specifically, there is a heat-fusible fiber that has heat-shrinkability but does not substantially heat-shrink at the crimp start temperature of the latent crimpable fiber, or a heat-fusible fiber that does not substantially have heat-shrinkability. (Hereinafter, these fibers are collectively referred to as non-heat-shrinkable fused fibers).

  The upper fiber layer 21 includes non-heat-shrinkable fused fibers. Specifically, the upper fiber layer 21 is preferably composed of a core-sheath type or side-by-side type heat fusion composite fiber. The upper fiber layer 21 may contain latent crimpable fibers contained in the lower fiber layer 22. Thereby, the recoverability when the raised portion 24 formed from the upper fiber layer 21 is compressed becomes high. In addition, the recoverability when the upper fiber layer 21 is extended in the plane direction is improved. From these viewpoints, the amount of the latent crimpable fibers contained in the upper fiber layer 21 is preferably 3 to 50% by weight, particularly 10 to 30% by weight.

  The lower fiber layer 22 is preferably hydrophilized from the viewpoint of smooth liquid permeation. Similarly, the upper fiber layer 21 is preferably subjected to a hydrophilic treatment. In this case, the lower fiber layer 22 preferably has a degree of hydrophilicity greater than that of the upper fiber layer 21. This makes it even more difficult for wetback to occur. Examples of the hydrophilization treatment include a method of imparting a hydrophilizing agent to the fiber surface or kneading the hydrophilizing agent into the fiber. Further, as a means for increasing the hydrophilicity of the lower fiber layer 22 over the upper fiber layer 21, fibers having a water absorption property (cellulose fiber, cotton, rayon, etc.) may be mixed into the lower fiber layer 22.

Next, the preferable manufacturing method of the nonwoven fabric 20 of this embodiment is demonstrated. First, the upper fiber layer 21 and the lower fiber layer 22 are manufactured. The upper fiber layer 21 is, for example, in the form of a web or non-woven fabric containing non-heat-shrinkable fusion fibers. Specifically, a card web is formed using a non-heat-shrinkable fusion fiber and, if necessary, a latent crimpable fiber as a raw material, and the upper layer is formed in the form of an air-through nonwoven fabric that is heat-treated by the air-through method. It can be used as the fiber layer 21. On the other hand, as the lower fiber layer 22, it is preferable to use a web containing 50% by weight or more of latent crimpable fibers from the viewpoint of the formation of the raised portion 24.
Then, the upper fiber layer 21 and the lower fiber layer 22 are laminated and embossed to obtain a nonwoven fabric in which both fiber layers are partially integrated at the heat-sealing portion 23. For embossing, a pair of roll devices or ultrasonic embossing devices heated to a predetermined temperature can be used.

Next, the obtained nonwoven fabric is heat-treated at a temperature equal to or higher than the crimp start temperature of the latent crimpable fiber. For example, hot air blowing (air-through processing) or infrared irradiation is used for the heat treatment. Due to the heat treatment, the lower fiber layer 22 contracts between the heat-sealed portions 23. However, the upper fiber layer 21 does not shrink. Therefore, the upper fiber layer 21 protrudes in the thickness direction of the nonwoven fabric as much as the shrinkage of the lower fiber layer 22, and a large number of raised portions 24 are formed. In this way, the nonwoven fabric 20 is obtained.
The degree of shrinkage of the nonwoven fabric is preferably 30 to 80%, particularly preferably 30 to 60% in terms of area shrinkage. The area shrinkage rate is expressed by the following formula (1), where S0 is the reference area before shrinkage and S1 is the area after shrinkage of the reference area.
Area shrinkage rate (%) = (S0−S1) / S0 × 100 (1)

  The absorbent core 4 in the napkin 1 is composed of an absorbent sheet 40 containing hydrophilic fibers and hot-melt adhesive fibers or paper strength reinforcing agents, and a superabsorbent polymer. The superabsorbent polymer 46 in the absorbent sheet 40 is In addition, it does not exist on the surface facing the top sheet 2 (hereinafter also referred to as an absorption surface), is distributed and arranged inside the absorbent sheet 40, and is bonded to the hydrophilic fibers constituting the absorbent sheet 40. Are fixed. Here, “not present on the surface facing the top sheet 2” does not mean that the superabsorbent polymer is not present at all on the surface of the absorbent sheet, and is preferably an absorbent sheet described later. In the production method, a small amount of superabsorbent polymer inevitably present on the surface of the absorbent sheet is acceptable, and it means that most of the superabsorbent polymer is present inside the absorbent sheet.

  The absorbent sheet 40 constituting the absorbent core 4 used in the present embodiment has a width approximately twice the width of the absorbent core 4, and both side portions thereof are opposite side edge portions 41 of the absorbent core 4, In 41, it is used as a two-layer structure by folding back to the back sheet 3 side. The absorbent sheet 40 may be used by being laminated in two or three layers without being folded, or may be used as a single layer.

The absorbent sheet 40 constituting the absorbent core 4 will be described in more detail.
The absorbent sheet 40 in this embodiment is comprised from the fiber assembly 45 and the fiber web 48, as shown in FIG. The fiber assembly 45 has an absorption surface 42 and does not include the superabsorbent polymer 46 on the absorption surface 42 side. On the other hand, the fiber web 48 is composed of at least hydrophilic fibers. Moreover, as shown in FIG. 3, the fiber assembly 45 and the fiber web 48 are integrated. Further, the superabsorbent polymer 46 is mainly disposed inside the fiber web 48 or between the fiber assembly 45 and the fiber web 46.

  Thus, a preferred embodiment of the absorbent sheet 40 used in the present invention has an integral structure including the fiber assembly 45 and the fiber web 48 and the superabsorbent polymer 46 included therein. More specifically, the fiber aggregate is formed by mechanical entanglement between the fibers constituting the fiber aggregate 45 and the fibers constituting the fiber web 48, hydrogen bonding (and paper strength reinforcing agent), heat fusion, and the like. 45 and the fiber web 48 are integrated. Such integration is preferably achieved by superposition by wet papermaking as described later.

  The fiber web 48 is in a wet state before the superabsorbent polymer 46 is sprayed, and the fibers constituting the fiber web 48 have a very high degree of freedom. By dispersing the superabsorbent polymer 46 on the fiber web 48 in such a state, the superabsorbent polymer 46 is three-dimensionally dispersed and fixed in the fiber web 48, that is, from the surface to the inside thereof. The fiber web 48 has such a strength that the superabsorbent polymer 46 does not precipitate on the surface of the absorbent sheet 40 after the fiber web 48 and the fiber assembly 45 are integrated. The fiber web 48 has a wet strength measured by JIS-P-8113 of preferably 50 g or more, and more preferably 100 g or more. In order to give wet strength to the fiber web 48, as will be described later, a hot-melt adhesive fiber or a paper strength reinforcing agent is blended. It is also preferable to add wood pulp or non-wood pulp that forms hydrogen bonds.

Fibrous web 48, the basis weight is preferably from 10g / m ² ~200g / m2, more preferably from ^{10g / m 2 ~100g / m 2} , more preferably at 20g / m ² ~80g / m ² is there.

  The fiber web contains at least hydrophilic fibers. Such a hydrophilic fiber can be used without particular limitation as long as it is a fiber having a hydrophilic surface and can form a fiber web having extremely high degrees of freedom in the wet state. Examples of such hydrophilic fibers include wood pulp such as softwood kraft pulp and hardwood kraft pulp, natural cellulose fibers such as cotton pulp and straw pulp, regenerated cellulose fibers such as rayon and cupra, polyvinyl alcohol fibers and polyacrylonitrile fibers, etc. These are synthetic fibers such as polyethylene fibers, polypropylene fibers, and polyester fibers, and the like, but are not limited thereto. These hydrophilic fibers can be used alone or in combination of two or more.

  The hydrophilic fiber is preferably contained in an amount of 30 parts by weight or more, more preferably 50 parts by weight or more based on 100 parts by weight of the fiber web.

Among the hydrophilic fibers, preferred are cellulose fibers. Cellulose fibers are preferred because they have a stable hydrophilic surface and maintain hydrophilicity even after wetting. In particular, bulky cellulose fibers such as natural cellulose fibers and regenerated cellulose fibers are preferred. From the viewpoint of cost, it is preferable to use wood pulp, and conifer kraft pulp is particularly preferable. By using such bulky cellulose fibers, not only the dispersibility and immobilization of the superabsorbent polymer can be further improved, but also the drainage of the fiber web can be more easily controlled during wet papermaking. . Furthermore, since the bulky cellulose fiber can form a bulky and highly porous fiber web, the superabsorbent polymer is easily embedded, dispersed and fixed three-dimensionally in the fiber web and is a gel of the superabsorbent polymer. The occurrence of blocking can also be suppressed. In addition, although there is no restriction | limiting in particular in the average fiber length of the said bulky cellulose fiber, As a general range, it is preferable that it is 1-20 mm. In addition, fibers obtained by hydrophilizing synthetic fibers such as PET, PE, and PP are also preferably used in the present invention as bulky hydrophilic fibers. In this specification, “bulky fiber” means that the fiber shape has a three-dimensional structure such as a twisted structure, a crimped structure, a bent and / or branched structure, or the fiber cross section is very thick (for example, the fiber roughness is high). 0.3 mg / m or more).
The bulky cellulose fiber is preferably contained in an amount of 30 parts by weight or more, more preferably 50 to 99 parts by weight, based on 100 parts by weight of the fiber web.

  Examples of preferred bulky cellulose fibers include cellulose fibers having a fiber roughness of 0.3 mg / m or more. Cellulose fibers having a fiber roughness of 0.3 mg / m or more are preferred because the cellulose fibers accumulate in a bulky state, so that a bulky network structure is easily formed in the fiber web. Further, it is preferable because the liquid movement resistance is small and the liquid passage speed is high. “Fiber roughness” is used as a measure of fiber thickness in fibers with non-uniform fiber thickness, such as wood pulp. For example, a fiber roughness meter (FS-200, KAJANNI ELECTRONICS LTD.). As described above, the bulky cellulose fiber preferably has a fiber roughness of 0.3 mg / m or more, more preferably a fiber roughness of 0.3 to 2 mg / m, and still more preferably a fiber roughness of 0. .2 to 1 mg / m.

  Examples of cellulose fibers having a fiber roughness of 0.3 mg / m or more and methods for measuring the fiber roughness are described in [0032] and [0094] of JP-A-8-246395. As another example of the preferred bulky cellulose fiber, the cellulose fiber having a roundness of the fiber cross section of 0.5 to 1, particularly preferably 0.55 to 1, the intramolecular and / or intermolecular range of the cellulose fiber. A crosslinked cellulose fiber that has been crosslinked may be mentioned. A method for measuring roundness is described in [0095] of JP-A-8-246395.

  Examples of the method for crosslinking the cellulose fiber include a crosslinking method using a crosslinking agent. Examples of such crosslinking agents include N-methylol compounds such as dimethylolethyleneurea and dimethyloldihydroxyethyleneurea; polycarboxylic acids such as citric acid, tricarballylic acid and butanetetracarboxylic acid; polyols such as dimethylhydroxyethyleneurea A cross-linking agent for polyglycidyl ether compounds. In particular, a crosslinking agent of a polycarboxylic acid or a polyglycidyl ether compound that does not generate formalin or the like harmful to the human body during crosslinking is preferable. The amount of the crosslinking agent used is preferably 0.2 to 20 parts by weight with respect to 100 parts by weight of the cellulose fiber. In addition to the above-described bulky cellulose fibers, bulky cellulose fibers in which the intramolecular and / or intermolecular molecules of cellulose fibers such as pulp having a fiber roughness of 0.3 mg / m or more are crosslinked by the above-described method are also preferable. . Moreover, the bulky cellulose fiber which bridge | crosslinked the molecule | numerator of the pulp whose fiber cross-section roundness is 0.5-1 and / or the molecule | numerator by the above-mentioned method is also preferable. Moreover, the bulky cellulose fiber which bridge | crosslinked the molecule | numerator and / or molecule | numerator of the mercerized pulp whose fiber cross section is 0.5-1 by the above-mentioned method is also preferable. The more preferable bulky cellulose fiber is obtained by crosslinking a pulp having a fiber roughness of 0.3 mg / m or more and a roundness of the fiber cross section of 0.5 to 1 by the above-described method. Particularly preferred bulky cellulose fibers are those having a fiber roughness of 0.3 mg / m or more and mercerized to roundness of 0.5 to 1 and then crosslinked by the method described above.

  In order to keep the structure stable even when the absorbent sheet is wet, it is necessary to give wet strength to the fiber web. For this purpose, hot-melt adhesive fibers or paper strength reinforcing agents are added. To do. Moreover, in order to strengthen the hydrogen bond between the fibers of cellulose fibers and improve the strength of the absorbent sheet, ordinary cellulose fibers, that is, wood pulp or non-wood pulp, can be used instead of the above hot melt adhesive fibers or the above paper strength reinforcing agent. It is also effective to add etc. However, in order to sufficiently obtain the wet strength of the absorbent sheet, it is preferable to use it in combination with a hot-melt adhesive fiber or a paper strength reinforcing agent.

  As the hot-melt adhesive fibers, fibers that are melted by heating and bonded to each other can be used. Specifically, for example, polyolefin fibers such as polyethylene, polypropylene, and polyvinyl alcohol, polyester fibers, and polyethylene-polypropylene. Examples thereof include a composite fiber, a polyethylene-polyester composite fiber, a low melting point polyester-polyester composite fiber, a polyvinyl alcohol-polypropylene composite fiber having a hydrophilic fiber surface, and a polyvinyl alcohol-polyester composite fiber. When using a composite fiber, any of a core-sheath type composite fiber and a side-by-side type composite fiber can be used. These hot-melt adhesive fibers can be used alone or in combination of two or more. Examples of the hot-melt adhesive fibers preferably used in the present invention include polyvinyl alcohol fibers that are dissolved in hot water, and core-sheath type polyester fibers.

In general, the heat-meltable adhesive fiber preferably has a fiber length of 2 to 60 mm, and a fiber diameter of 0.1 to 3 dtex (particularly 0.5 to 3 dtex).
As described above, examples of the paper strength reinforcing agent added to the fiber web include polyamine / epichlorohydrin resin, dialdehyde starch, sponge, and carboxymethylcellulose. These paper strength reinforcing agents can be added in an amount of 0.01 to 30 parts by weight, preferably 0.01 to 20 parts by weight, based on 100 parts by weight of the fiber web.
When using the hot melt adhesive fibers, the fiber web comprises 30 to 99 parts by weight of the hydrophilic fiber and 1 to 50 parts by weight of the hot melt adhesive fiber based on 100 parts by weight of the fiber web. Is preferred. More preferably, it comprises 50 to 97 parts by weight of the hydrophilic fiber and 3 to 30 parts by weight of the hot-melt adhesive fiber based on 100 parts by weight of the fiber web.

  The fiber web preferably includes, for example, 1 to 10 parts by weight of vinylon fiber (polyvinyl alcohol fiber), and more preferably 2 to 5 parts by weight. As the vinylon fiber, it is preferable to use a vinylon fiber that dissolves with wet heat. As another example, the fiber web preferably comprises 1 to 30 parts by weight, more preferably 5 to 20 parts by weight of a hot-melt adhesive fiber having a core-sheath structure. As a specific example of the above-mentioned heat-meltable adhesive fiber having a core-sheath structure, a sheath is a polyethylene-vinyl acetate resin having a melting point of 70 ° C. to 150 ° C., a polyethylene resin, or a modified polyester resin, or wet heat-soluble polyvinyl alcohol. In addition, a synthetic fiber having a core-sheath structure in which a polypropylene resin or a polyester resin is used as a core can be given.

  On the other hand, when the paper strength reinforcing agent is used, the hydrophilic fiber is 30 to 100 parts by weight, the other fibers are 0 to 50 parts by weight, and the paper strength reinforcing agent is 0.01 based on 100 parts by weight of the fiber web. It is preferable that -30 weight part is contained. More preferably, based on 100 parts by weight of the fiber web, 50 to 100 parts by weight of the hydrophilic fiber, 0 to 20 parts by weight of other fibers, and 0.01 to 20 parts by weight of the paper strength reinforcing agent are included. For example, the fiber web comprises 30 to 99 parts by weight of the bulky cellulose fiber, 1 to 70 parts by weight of the wood pulp or non-wood pulp, and the paper strength reinforcing agent based on 100 parts by weight of the fiber web. It preferably contains 0.01 to 30 parts by weight. More preferably, based on 100 parts by weight of the fiber web, the bulky cellulose fiber is 50 to 95 parts by weight, the wood pulp or non-wood pulp is 5 to 50 parts by weight, and the paper strength reinforcing agent is 0.01 to Contains 20 parts by weight.

  The superabsorbent polymer 46 contained in the absorbent sheet 40 will be described. As shown in FIG. 2 and FIG. 3, the superabsorbent polymer 46 is contained in the absorbent sheet 40 and is dispersed in the spaces formed between the fibers constituting the absorbent sheet 40. More specifically, as shown in FIG. 3, the superabsorbent polymer 46 is mainly contained from the interface between the fiber web 48 and the fiber assembly 45 to the inside of the fiber web 48. It is preferably dispersed in the space formed between the constituent fibers. As a result, the superabsorbent polymer 46 is reliably fixed in the absorbent sheet and the occurrence of gel blocking is suppressed.

  The superabsorbent polymer 46 is bonded to the hydrophilic fibers constituting the absorbent sheet 40, preferably the hydrophilic fibers constituting the fiber web 48. Here, the superabsorbent polymer 46 is mainly bonded to the hydrophilic fiber, but there is no problem even if it is bonded to another fiber constituting the absorbent sheet, for example, a heat-meltable fiber. Also, it is not necessary for all the particles to adhere to the fiber. Based on the total amount of the superabsorbent polymer 46, 50% by weight or more is preferably bonded to the fiber, and particularly 70% by weight or more is preferably bonded to the fiber. A method for bonding the superabsorbent polymer 46 to the fiber will be described later.

  In addition, as a superabsorbent polymer, when a particle agglomeration type superabsorbent polymer in which a spherical polymer is agglomerated as a primary particle to form a secondary particle is used, all of the primary particles adhere to the fiber. If the secondary particles are partly adhered to the fiber, the superabsorbent polymer is fixed to the fiber.

Preferably, the superabsorbent polymer 46 is not dispersed in a layered manner in the absorbent sheet 40, but is dispersed three-dimensionally as shown in FIG. Thereby, the upper limit of the application | coating basic weight of the superabsorbent polymer 46 can be about 200-300 g / m < ² >. Furthermore, since the superabsorbent polymer 46 is dispersed three-dimensionally, the original absorbent performance of the superabsorbent polymer 46 is more effectively expressed. That is, even when the same amount of superabsorbent polymer as that of the conventional absorbent sheet is used, the absorption performance can be further improved and the absorbent sheet can be made extremely thin. In addition, since the spreading basis weight can be increased, it can be suitably used as an absorbent body such as a paper diaper that requires a large absorption capacity.

The superabsorbent polymer has a spreading basis weight of 5 to 300 g / m ² , and preferably 10 to 250 g / m ² .

  As the superabsorbent polymer 46, a polymer that can absorb and hold a liquid 20 times or more of its own weight and can be gelled is preferable. The shape is not particularly limited and is spherical, massive, grape-like, powdery or fibrous, and preferably has a particle size of 1 to 1000 μm (more preferably 10 to 500 μm). Examples of such superabsorbent polymers include polyacrylic acid and salts thereof, and polyacrylate graft polymers such as starch, crosslinked carboxylmethylated cellulose, polymers or copolymers of acrylic acid or alkali metal acrylates. Coalescence can be mentioned. As the polyacrylic acid salt, a sodium salt can be preferably used. In addition, a comonomer such as maleic acid, itaconic acid, acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, 2- (meth) acryloylethanesulfonic acid, 2-hydroxyethyl (meth) acrylate or styrenesulfonic acid is added to acrylic acid. Copolymers copolymerized within a range that does not deteriorate the performance of the superabsorbent polymer can also be preferably used.

  Next, the fiber assembly 45 having the absorbent surface 42 in the absorbent sheet 40 will be described. Here, the “absorbing surface” refers to a surface that absorbs liquid mainly when the absorbent sheet 40 absorbs liquid. That is, in a preferred embodiment of the absorbent sheet 40, the liquid is mainly absorbed from the fiber assembly 45 side.

  The fiber assembly 45 does not contain the superabsorbent polymer on the absorption surface side (the superabsorbent polymer does not exist). Here, “not including the superabsorbent polymer” does not mean that the fiber aggregate does not contain the superabsorbent polymer at all on the absorption surface side, and a preferable method for manufacturing the absorbent sheet described later This means that a very small amount of superabsorbent polymer inevitably mixed in can be allowed but substantially does not contain the superabsorbent polymer on the absorption surface side.

  The fiber assembly 45 is obtained by mechanical entanglement, physical entanglement, thermal bonding, or the like of the fiber, and for example, paper or nonwoven fabric can be used. As the paper, paper obtained by wet papermaking or creped paper can be used. On the other hand, as the nonwoven fabric, various nonwoven fabrics such as a card method nonwoven fabric, a spunbond nonwoven fabric, and a spunlace nonwoven fabric mainly composed of synthetic cellulose fibers such as rayon and cupra and natural cellulose fibers such as cotton can be used.

  The fiber assembly 45 preferably includes hydrophilic fibers. As such hydrophilic fibers, the same fibers as those used in the above-mentioned fiber web can be used. The hydrophilic fiber is preferably contained in an amount of 30 parts by weight or more based on 100 parts by weight of the fiber assembly, and more preferably 50 to 99 parts by weight.

  It is preferable that wet strength is imparted to the fiber assembly 45 as in the case of the fiber web. The wet strength of the fiber assembly is preferably 50 g or more, more preferably 100 g or more, as measured by JIS-P-8113. The method for imparting wet strength to the fiber assembly is the same as that for the fiber web. The above-mentioned hot-melt adhesive fiber or paper strength reinforcing agent is blended. It is also preferable to add wood pulp or non-wood pulp that forms hydrogen bonds. In this case, the heat-meltable adhesive fiber is preferably contained in an amount of 1 to 50 parts by weight, more preferably 3 to 30 parts by weight, based on 100 parts by weight of the fiber assembly. The paper strength reinforcing agent is preferably included in an amount of 0.01 to 30 parts by weight, more preferably 0.02 to 20 parts by weight, based on 100 parts by weight of the fiber assembly. The fiber assembly is particularly preferably formed by the same blending as the fibers and components forming the fiber web. The fiber assembly is also preferably made of a nonwoven fabric, particularly preferably a dry method nonwoven fabric, for example, a card method nonwoven fabric.

The fiber aggregate preferably has a basis weight of 10 to 200 g / m ^2, and still more preferably from 10 to 100 g / m ^2.

In the absorbent sheet used in the present invention, the basis weight of the fiber assembly is 10 to 200 g / m ² , the scattering basis weight of the superabsorbent polymer is 5 to 300 g / m ² , The basis weight is preferably 10 to 200 g / m ² , the basis weight of the fiber assembly is 10 to 100 g / m ² , and the scattering basis weight of the superabsorbent polymer is 5 to 200 g / m ² . The basis weight of the fiber web is more preferably 10 to 100 g / m ² .

Moreover, basis weight of the total of the absorbent sheet used in the present invention is preferably 21~500g / m ^2, more preferably from 30~300g / m ^2, is 50 to 200 g / m ² Is more preferable. Further, the absorbent sheet used in the present invention preferably has a fiber density of 0.1 g / cm ³ or more, more preferably from 0.1 to 0.4 g / cm ^3, 0.1-0 More preferably, it is 2 g / cm ³ . By setting the fiber density in such a range, gel blocking of the superabsorbent polymer is more effectively prevented. The fiber density in such a range can be easily realized by using bulky hydrophilic fibers (particularly bulky cellulose fibers).

The absorbent sheet used in the present invention is particularly preferably composed of a bulky hydrophilic fiber, a fiber structure formed from a hot-melt adhesive fiber or a paper strength reinforcing agent, and a superabsorbent polymer particle. The superabsorbent polymer particles do not exist on the absorbing surface where the absorbent sheet absorbs liquid, are dispersed and fixed in the fiber structure, and the thickness of the absorbent sheet is 0.3 to 1.5 mm. and is a absorbent sheet spread basis weight of the high absorbent polymer is 20 to 70 g / m ^2. Such an absorbent sheet is extremely thin. Further, if a large amount of liquid is not absorbed, there is almost no increase in thickness even after absorption of the liquid. Therefore, when such an absorbent sheet is used, for example, as an absorbent core of a sanitary napkin, a comfortable feeling without discomfort can be obtained even after absorption of menstrual blood.

When the absorbent article of the present invention is a sanitary napkin, the application basis weight of the superabsorbent polymer in the absorbent sheet is preferably 10 to 100 g / m ² , more preferably 20 to 70 g / m ² , The basis weight of the fiber aggregate is preferably 10 to 80 g / m ² , more preferably 15 to 50 g / m ² , and the basis weight of the fiber web is preferably 10 to 80 g / m ² , more preferably 15 to 50 g / m ² . m ² , and the thickness of the absorbent sheet is preferably 0.3 to 1.5 mm. On the other hand, when the absorbent article of the present invention is a disposable diaper, the application basis weight of the superabsorbent polymer in the absorbent sheet is preferably 50 to 300 g / m ² , more preferably 100 to 250 g / m ² . The basis weight of the fiber assembly is preferably 20 to 200 g / m ² , more preferably 20 to 100 g / m ² , and the basis weight of the fiber web is preferably 20 to 200 g / m ² , more preferably 20 to 100 g. / M ² , and the thickness of the absorbent sheet is preferably 0.5 to 1.5 mm.

  Next, a preferable method for producing the absorbent sheet used in the present invention is described in paragraphs [0079] to [0087] of JP-A-8-246395. The method is a method for producing an absorbent sheet comprising at least a hydrophilic fiber and a hot-melt adhesive fiber or paper strength reinforcing agent and a superabsorbent polymer, and at least the hydrophilic fiber and the hot-melt adhesive fiber or paper strength reinforcement. A fiber assembly containing a hydrophilic fiber and a heat-melting adhesive fiber or a paper strength reinforcing agent on a wet fiber web, which is made by wet papermaking of an aqueous slurry containing an agent. And the steps of drying and uniting them.

The outline of the method will be described. First, the fiber web containing the hydrophilic fibers is formed. As a method for forming the fiber web, a dry papermaking method or the like can be used, but a wet papermaking method is preferably used.
When wet-making a fiber web, the fibers and components that form the fiber web, preferably the hydrophilic fiber, the hot-melt adhesive fiber, or the paper strength reinforcing agent, etc. are adjusted to a predetermined concentration. The slurry is dispersed in water to form a slurry.

  Next, a superabsorbent polymer is sprayed on the obtained fiber web in its wet state. The wet state of the fiber web is preferably about 20 to 500 parts by weight of water based on 100 parts by weight of the dry fiber web, and more preferably contains 50 to 300 parts by weight of water. By spraying the superabsorbent polymer on the wet fiber web, the superabsorbent polymer absorbs water and becomes sticky, and is buried in the fibers constituting the fiber web, and then dried. Bond and fix to fiber. Further, since the fiber web in a wet state has a degree of freedom because the fibers constituting it are not yet bonded to each other, the superabsorbent polymer can be dispersed three-dimensionally.

Next, the fiber assembly is superimposed on the surface of the fiber web on which the superabsorbent polymer is dispersed. At this time, since the fibers in the fiber web still have a degree of freedom, the superabsorbent polymer is buried in the fiber web and the fibers in the fiber web and the fibers in the fiber assembly. Easily intertwine.
Subsequently, by drying the laminated body of the fiber web and the fiber assembly, the fibers are entangled with each other, and further, the action of hydrogen bonding and heat fusion is added, and the fiber web and the fiber assembly are And the superabsorbent polymer adhering to the fiber dries and adheres to obtain an absorbent sheet that can be preferably used in the present invention. As a drying means, for example, a Yankee dryer or an air-through dryer is used.

In the napkin 1 of this embodiment, the nonwoven fabric 20 which comprises the surface sheet 2 and the absorbent sheet 40 which comprises the absorbent core 4 are in direct contact. In the schematic diagram shown in FIG. 2, there appears to be a gap between the lower fiber layer 22 of the nonwoven fabric 20 and the surface (absorbing surface) 42 facing the top sheet in the absorbent sheet 40 constituting the absorbent core 40. In reality, however, the lower fiber layer 22 and the liquid absorbing surface 42 of the absorbent sheet 40 are in contact with each other over substantially the entire surface except for the heat fusion part 23.
In a conventional general absorbent body such as an absorbent body in which scattered fibers and / or superabsorbent polymers are sucked and deposited on a mount and the deposit is wrapped with the mount, The absorbent core in which the superabsorbent polymer is held is usually covered with a tissue or the like constituting the mount. In addition, a fiber assembly layer called a second sheet, a sublayer, or a cushioning material is widely provided between the surface sheet and the absorbent core in the absorbent article in order to improve liquid return and cushioning properties. On the other hand, in this embodiment, the absorption speed is greatly improved by bringing the nonwoven fabric 20 constituting the top sheet 2 and the absorbent sheet 40 constituting the absorbent core 4 into direct contact.

In the napkin 1 of the present embodiment, a pattern coating is applied between the nonwoven fabric 20 constituting the top sheet 2 and the absorbent sheet 40 constituting the absorbent core 4 as shown in FIGS. Partially bonded by the adhesive 6. By being bonded via the pattern-coated adhesive, the contact state between the nonwoven fabric 20 and the absorbent sheet 40 is stably maintained and at the same time, liquid absorption is not inhibited, An excellent liquid absorption rate can be achieved. In addition, even in the removal of the superabsorbent polymer from the cross section of the absorbent sheet, the degree of freedom is suppressed because the topsheet and the backsheet are joined by the pattern-coated adhesive, and the superabsorbent polymer is prevented from falling off. Omission from the surface sheet is suppressed.
Pattern coating is a coating method that occurs in a state where a portion where an adhesive is disposed and a portion where an adhesive is not disposed are mixed. The adhesive 6 in the napkin 1 of this embodiment is applied in a spiral pattern as shown in FIG. In addition, the inside of the range shown with the code | symbol 4 'in FIG. 4 has overlapped with the absorptive core 4, and is the range joined with the absorptive core 4 with the adhesive agent by which pattern coating was carried out.

Examples of the pattern coating pattern include a spiral pattern, a dot pattern, a stripe pattern (striped pattern), a lattice pattern, and a checkered pattern.
Examples of the dot pattern include a pattern in which a large number of individual bonded portions having a plan view shape such as a circle, a rhombus, an ellipse, etc. are formed in a dotted pattern. Stripe patterns (striped patterns) include those in which a large number of linear adhesive portions are generated in parallel, a pattern in which a large number of linear adhesive portions are generated in a non-parallel manner, a continuous waveform, a zigzag shape, etc. The thing which produces many linear adhesive parts in parallel or non-parallel can be mentioned. The stripe pattern that generates a large number of parallel linear adhesive portions is that each adhesive portion extends in the longitudinal direction or the width direction of the absorbent article and is inclined with respect to the longitudinal direction and the width direction. It may be (an oblique stripe).
Examples of the grid pattern include a pattern in which linear adhesive portions are formed in a grid shape, and a pattern in which a plurality of continuous wave-shaped adhesive portions extending substantially in one direction are arranged vertically and horizontally.

The area ratio (100% of the whole surface solid coating) of the adhesive-coated part to the polymerization area of the absorbent sheet 40 and the nonwoven fabric 20 (same as the area of the absorbent sheet 40 facing the nonwoven fabric) is 1 to 10%, especially 2 It is preferably ˜5%.
In the napkin 1 of the present embodiment, the absorbent core 4 and the back sheet 3 are also bonded by the pattern-coated adhesive 7. However, the absorbent core 4 and the back sheet 3 may be bonded on the entire surface or may not be bonded at all.

In the napkin 1 of this embodiment, the nonwoven fabric 20 constituting the top sheet 2 and the absorbent sheet 40 constituting the absorbent core 4 are partially joined by embossing as shown in FIGS. 1 and 2. Has been. In the present embodiment, a large number of joint portions (crimped portions) 11 formed by embossing are arranged in series so as to form an annular shape in a plan view.
Partial bonding by embossing is performed, for example, between a surface sheet and an absorbent core between both rolls in a heat embossing apparatus provided with an embossing roll having irregularities of a predetermined pattern formed on a peripheral surface and an anvil roll having a smooth surface. Are inserted in a laminated state, and a large number of mutually spaced portions in the plane direction are hot-pressed on the laminated body.
As a form of formation of the joint portion by embossing, there may be mentioned one in which individual embosses (crimped portions) such as a circle, an ellipse, a rectangle, a rectangle, and a rhombus are arranged apart from each other to form a desired pattern. As an example, FIGS. 6A and 6B show an oblong pattern formed by arranging rectangular and rectangular embosses. As a more preferable form of forming the joining portion, as shown in FIG. 6 (c), there may be mentioned one in which the individual embosses of the straight portions of the oval pattern are arranged obliquely with respect to the longitudinal direction of the oval. By providing such a pattern of embossing in the central region, the excreted liquid is prevented from leaking in the lateral direction. FIG. 6D shows an arcuate emboss pattern as a modification.

When the joint part by embossing of a surface sheet and an absorber consists of many crimping | compression-bonding parts arrange | positioned intermittently, the space | intervals (crimp part edge part distance) between crimping parts shall be 3 mm or less, especially 2 mm or less. Is preferred.
The area ratio of the embossed portion (joint portion) to the polymerization area of the absorbent sheet 40 and the nonwoven fabric 20 (same as the area of the nonwoven fabric facing surface of the absorbent sheet 40) (100% full-surface joining) is 1 to 10%, particularly 1 It is preferably ˜5%.

According to the napkin 1 of this embodiment, since the crimping | compression-bonding part formed by compressing the surface sheet 2 and the absorptive core 4 integrally by embossing is formed in the central area in the excretion part opposing part. The top sheet is integrated with the absorber while the fibers constituting it are stretched.
Therefore, the topsheet is fixed to the absorbent body in a state where tension is applied between the crimping portions between the embosses, and even if deformation or the like occurs in the absorbent article due to movement of the body during wearing, the topsheet and Adhesiveness with the absorber is well maintained, and the liquid excreted (supplied) on the top sheet is quickly transferred to the absorber and absorbed.
Moreover, since the fibers of the top sheet are integrated with the absorbent body while being stretched, the fibers are fused and / or engaged to a deeper position in the thickness direction of the absorbent body. Therefore, the liquid excreted (supplied) on the top sheet quickly moves to the absorbent body, and the top sheet is not easily detached from the absorbent body, so that the structure is stable with respect to body movement.
According to the napkin 1 of the present embodiment, the liquid residue and the liquid flow on the top sheet can be prevented by such an action, and an excellent absorption performance and leakage prevention performance are expressed and a comfortable feeling with reduced wet feeling is achieved. A feeling of wearing can be obtained.

  As a material for forming the back sheet 3 and the side sheet 5, various known materials conventionally used for sanitary napkins, disposable diapers and the like can be used without particular limitation. For example, as the back sheet 3, a polyethylene film, a polypropylene film, a polyester film, or the like can be used. These films may be provided with fine holes for air permeability. Moreover, a highly water-resistant nonwoven fabric such as an SMS nonwoven fabric can be used. As the side sheet 5, considering the softness to the skin, the feeling of cushioning, and the leakproof property, a non-woven material having high water resistance and water repellency is preferably used. Specifically, fibers made of polyethylene, polypropylene, polyester, or composite materials made of nonwoven fabric by the card method, spunbond method, melt blow method, etc. are used. The suction heat bond nonwoven fabric which adhere | attaches the web obtained by the method with hot air is used preferably, and when attaching importance to water resistance, a spun bond nonwoven fabric or SMS is preferably used. In any of the nonwoven fabrics, considering the softness of the surface and water resistance, the thickness of the fibers is preferably a nonwoven fabric produced with fibers of 3 dtex or less. Moreover, as a nonwoven fabric to be used, in order to stably form the shape stability in the width direction and the ridges, those obtained by subjecting the nonwoven fabric to embossing in advance can be preferably used.

The present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the spirit of the present invention.
For example, the absorbent article of the present invention may be a panty liner (cage sheet), an incontinence pad, etc. in addition to a sanitary napkin. Absorbent articles such as sanitary napkins may be provided with no side sheets.
Moreover, you may not have the partial junction part by the embossing between the nonwoven fabric which comprises a surface sheet, and the absorbent sheet which comprises an absorptive core.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further in detail, it cannot be overemphasized that this invention is not limited to these Examples. In the following description, “parts” means “parts by weight” unless otherwise specified.

[Example 1]
(1) Manufacture of surface sheet (1-1) Manufacture of upper fiber layer As non-heat-shrinkable fused fiber, core-sheath type composite fiber (trade name NBF-SH, core: polyethylene terephthalate, sheath manufactured by Daiwa Boseki Co., Ltd.) : Polyethylene, core / sheath weight ratio = 5/5, fineness 2.2 dtex, fiber length 51 mm). This fiber was defibrated using a card machine to form a web, which was then heat treated by an air-through method (120 ° C.) to obtain an air-through nonwoven fabric having a basis weight of 20 g / m ² .

(1-2) Manufacture of lower fiber layer Latent crimpable fiber (core-sheath type composite fiber having heat shrinkability with ethylene-propylene random copolymer as core component and polypropylene as sheath component, fineness of 2.2 dtex, A card web was produced in the same manner as the upper fiber layer, using Daiwabo Co., Ltd. (crimping start temperature 90 ° C.) as a raw material. The basis weight of the obtained card web was 20 g / m ² .

(1-3) Manufacture of surface sheet The upper fiber layer and the lower fiber layer are superposed and passed through a hot embossing roll device comprising a combination of an engraving roll and a smooth roll, and both layers are partially joined and integrated to obtain a nonwoven fabric. It was. The embossing pattern of the engraving roll was a so-called houndstooth pattern.
The obtained nonwoven fabric was heat-treated for 1-2 minutes in a heat dryer heated to 130 ° C. The obtained non-woven fabric had a basis weight of 80 g / m ² , and the lower fiber layer contracted between the heat-sealed portions, thereby forming a bulged portion that was greatly raised as shown in FIG.

(2) Production of Absorbent Sheet Chemical pulp having a fiber roughness of 0.18 mg / m and a fiber cross-section roundness of 0.32 [conifer kraft pulp, Skena Cellulose Co. SKEENA PRIME (trade name) made in water was dispersed and mixed in water, and paper strength reinforcing agent [polyamide epichlorohydrin resin, trade name; Kaimen WS-570, company name; Ltd.] was dispersed and mixed with a resin component in water, and a fiber web was formed by using this dispersion mixture in a forming part of a wet paper machine so that the dry basis weight was 40 g / m ² . Next, the fiber web was dehydrated with a suction box until the water content was 200 parts based on 100 parts of the dry fiber web. Next, immediately before the press part, the superabsorbent polymer was sprayed almost uniformly at a spraying basis weight of 50 g / m ² on the wet fiber web after dehydration.

Absorbent paper (basis weight 40 g / m ² ) that has been made in advance and has the same composition as the fiber web as a fiber aggregate on the surface of the fiber web on which the superabsorbent polymer is dispersed. One sheet of absorbent with a superabsorbent polymer fixed inside by superposing and introducing a laminated body of such fiber web and absorbent paper into a dryer, drying and integrating at a temperature of 130 ° C. A sheet was obtained.

(3) Manufacture of sanitary napkin The sanitary napkin of the form shown in FIGS. 1-3 was manufactured using the nonwoven fabric and absorbent sheet which were obtained as mentioned above. The nonwoven fabric and the absorbent sheet were joined in a spiral pattern as shown in FIG. 3 with a hot-melt adhesive. Moreover, the area ratio of the adhesion part with respect to the polymerization area of a nonwoven fabric and an absorptive sheet was 3%. As the back sheet 3, a polyethylene film (basis weight 40 g / m ² ) provided with fine holes for air permeability was used. As the side sheet 5, an air-through nonwoven fabric (basis weight 20 g / m ² ) heat-treated by an air-through method using a core-sheath type composite fiber (core: polyethylene terephthalate, sheath: polyethylene) was used.

[Comparative Example 1]
Using a nonwoven fabric and an absorbent sheet obtained in the same manner as in Example 1, an air-through method using a core-sheath type composite fiber (core: polyethylene terephthalate, sheath: polyethylene) between the surface material and the absorbent sheet. A second sheet made of an air-through nonwoven fabric (basis weight 40 g / m ² ) obtained by heat treatment in the above is interposed, and the nonwoven fabric and the second sheet are joined with hot melt (basis weight 4 g / m ² ) by spiral coating. A sanitary napkin was prepared in the same manner as in Example 1 except that the second sheet and the absorbent sheet were joined with a hot melt (basis weight 5 g / m ² ) by spiral coating.

  The obtained sanitary napkin was evaluated by the following method. The results are shown in Table 1.

<Absorption rate>
As shown in FIG. 5, a bottomed cylindrical body (bottom area 11 cm ² , weight 100 g) 81 having five holes with a diameter of 3 mm on the bottom surface is placed on the central portion (urination point) of the sanitary napkin, The bottomed cylindrical body 81 has a bottomed cylindrical shape with a speed that does not overflow 10 g of artificial urine (saline colored with edible red No. 2; hereinafter the same) using the funnel 82 in the bottomed cylindrical body 81. The liquid was injected from the bottom of the body at such a rate that the liquid did not disappear.
And the time until 10 g of artificial urine in the bottomed cylindrical body 81 was absorbed by the sanitary napkin was measured.

<Surface liquid remaining amount>
5 g of artificial urine is dropped at the center of the sanitary napkin (urination point) at a rate of 5 g / second, and after standing for a certain period of time (indicated as the elapsed time in Table 1), the artificial urine is absorbed into eight parts. One piece of the tissue was stacked, and a weight of 4 g / cm ² was further applied thereon, and the weight was taken out after 5 seconds. The weight of the artificial urine absorbed in the tissue was taken as the remaining liquid amount.

<Surface diffusion area>
5 g of artificial urine was dropped at the center of the sanitary napkin (urination point) at a rate of 5 g / sec, and the area where the artificial urine spread immediately after the dropping was measured.

  As is clear from the results shown in Table 1, the absorbent article of the present invention has a higher absorption rate and less surface liquid residue than those in which a second sheet is interposed between the nonwoven fabric and the absorbent sheet. And spot absorptivity.

FIG. 1 is a plan view showing a sanitary napkin according to an embodiment of the present invention as viewed from the surface sheet side. 2 is an enlarged schematic cross-sectional view taken along line II-II in FIG. FIG. 3 is a cross-sectional view showing an example of an absorbent sheet. FIG. 4 is a view showing a coating pattern of an adhesive for joining the topsheet and the absorbent sheet in the sanitary napkin of FIG. 1, and is a view of the topsheet as seen from the absorbent core side. FIG. 5 is an explanatory diagram of a method for measuring the absorption rate. FIG. 6 is a schematic plan view showing an arrangement example of partial joint portions by embossing between the nonwoven fabric constituting the top sheet and the absorbent sheet constituting the absorbent core.

Explanation of symbols

1 Sanitary napkin (absorbent article)
2 Top sheet 21 Upper fiber layer (upper layer)
22 Lower fiber layer (lower layer)
23 Heat-fusion part 24 Raised part 3 Back sheet 4 Absorbent body 40 Absorbent sheet 42 Absorbing surface (surface facing the top sheet)
46 Superabsorbent polymer 5 Side sheet 6 Adhesive

Claims (4)

An absorbent article comprising a top sheet, a back sheet and an absorbent core interposed between the two sheets,
The top sheet is made of a non-woven fabric having a large number of heat-sealed portions formed by embossing, and a large number of fibers constituting the non-woven fabric project between at least the skin-facing surfaces of the non-woven fabric. Forming the ridge of
The absorbent core is composed of an absorbent sheet containing hydrophilic fibers and hot-melt adhesive fibers or paper strength reinforcing agents, and a superabsorbent polymer,
The absorptive article in which the nonwoven fabric which constitutes the surface sheet, and the absorptive sheet which constitutes the absorptive core are in direct contact.   The absorbent article according to claim 1, wherein the nonwoven fabric constituting the surface sheet and the absorbent sheet constituting the absorbent core are partially joined by a pattern-coated adhesive.   The absorbent article according to claim 1, wherein the nonwoven fabric constituting the surface sheet and the absorbent sheet constituting the absorbent core are partially joined by embossing. The non-woven fabric has an upper layer and a lower layer adjacent to the upper layer, the raised portion formed on the skin-facing surface side of the non-woven fabric is composed of an upper layer, and the latent crimpable fiber in which crimps are expressed in the lower layer Is contained in an amount of 50% by weight or more, and the upper layer contains a heat-fusible fiber that is substantially not heat-shrinkable or that does not heat-shrink at a temperature equal to or lower than the crimp start temperature of the latent crimpable fiber. Item 4. The absorbent article according to any one of Items 1 to 3.

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